Catalytic hydrogenation of aliphatic carboxylic acid anhydrides



Patented June is, 1943 CATALYTIC HYDROGENATION F ALI- rns'no CARBOXYLICACID summons,

Otto Schmidt, Heidelberg, Germany, assi nor, by mesne assignments, toGeneral Aniline & Film Corporation, New York, N. Y., a corporation ofDelaware No Drawing. Original application April 1,1931,

Serial No. 527,060.

Divided and this application June 26, 1941, Serial No. 399,927. InGermany November 20, 1925 12 Claims. (01. 260-638) This application is adivision of Ser. No. 527,060, filed April 1, 1931.

The present invention relates to the reduction of organic acids andcertain derivatives thereof to alcohol and/or esters and mixturesessentially consisting of or containing preponderating quantities of thesaid products.

It is already known that esters of fatty acids of low molecular weightand the corresponding anhydrides can be educed in the gaseous phase withthe aid of hydrogen and of metallic hydrogenation catalysts atatmospheric pressure. In most cases, however, as for example in thereduction of acetic ethyl ester heterogeneous products have beenobtained which contained some aldehyde and olefines. Even the reductionof anhydrides in the liquid phase with noble metal hydrogenationcatalysts, such as palladium, and at slightly elevated pressure up to 4atmospheres furnished heterogeneous products consisting mainly ofaldehydes.

I have found that in organic compounds having at least 2 carbon atomsand containing a carboxylic acid radicle (i. e. at least 2 oxygen tivescontaining at least 2 oxygen atoms connected to one carbon atom,especially of those acids which contain at least 8 carbon atoms in theirmolecule, the free or latent carboxylic groups can be reduced toalcoholic groups by treating the said compounds in the liquid state atan elevated temperature with hydrogen in the presence of hydrogenationcatalyst at a pressure of at least 30 atmospheres until thesaponification value of the initial materials is considerablydiminished. In order to obtain good results it is usually necessary towork under energetic conditions at increased temperatures, such as above120 C.

An efiicient activation of the catalysts can be obtained by a very finedisintegration of the catalytic substances, for example by employing thecatalytic substances alone in a very finely divided form, or bydepositing the catalytic subs ances on large surface carriers, such asfibrous asbestos, powdered graphite, silica gel or inert metal powdersand the like, and/or by adding to the catalytic substance one or moreactivating substances. Suitable catalytic substances are for example thebase metals, copper, nickel, iron,

corporation with activating substances.

be prepared from their salts, oxides or other compounds, if desiredprior to or after an in- Compounds of metals which are converted intothe metals during the operation may be also employed, as for examplesalts of cobalt with any organic carboxylic acids. The activatingsubstances may be chosen from compounds of the solid metallic elementsof the 1st to 7th groups of the periodic system as for example fromcomcobalt or silver or mixtures thereof and they may pounds, such ashydroxides, oxides, carbonates. phosphates, silicates, nitrates, or alsocyanides complex compounds as for example iron-cyanides and the like, ofthe alkali or the alkaline earth or rare earth metals, such aspotassium, sodium, calcium, barium or magnesium, lanthanum, thorium,cerium and zirconium, further boron and articularly from compounds ofthe metals giving acids with oxygen, such as chromium, molybdenum,tungsten, uranium, manganese, vanadium or titanium or mixtures thereofas well as salts of the metal acids or several of these compounds.

employed in the form of the alkali metal, alkaline earth metal or rareearth metal salts of the said acids or in the form of their salts withthe hydrogenating metals, as for example copper, nickel, cobalt, iron,silver or zinc vanadates, molybdates, manganic salts, uranates,tungstates and the like and in this case the said hydrogenating metalsmust not be present as such. The solid metals of the 2nd to 4th groupsof the periodic system, as for exampl zinc, cadmium, tin, and aluminummay also be employed in the free state for activating purposes, the saidcheap and easily available metals being preferred. The order of mixingthe aforesaid single components is not important and, as already stated,the activating substances may be mixed with compounds of thehydrogenating metals, whereupon the whole mass is subjected to atreatment with hydrogen, whereby reducible compounds of thehydrogenating metals are converted wholly or at least partially into thefree metals. Otherwise the components may be mixed for example in a meltof fusible activating substances, such as alkali metal compounds, towhich the hydrogenating metals or the compounds are added. In cases whencompounds are to be hydrogenated which still .contain catalyst poisons,such as animal fats containing albuminous matter, catalysts immune frompoisoning, as for example those containing molybdenum or its compoundsalone or in admixture with other substances may be employed.

By suitably selecting the catalyst as well as the reaction temperatureand the pressures, the reduction can be carried either to a well definedstage, i. e. t) the formation of products which contain alcoholic groupsor even to products in which the original carboxyl groups are reduced tohydrocarbon radicles. Thus, for example, soya bean oil can be reduced toa mixture of pure alcohols corresponding to the fatty acids of theoriginal oil. In many cases catalysts consisting of nickel provide moreenergetic reduction than catalysts prepared from cobalt or copper, whichlatter are particularly valuable for the production of alcohols, whereasthe employment of a highly active nickel catalyst may lead to areduction to the hydrocarbon stage, especially at higher temperatures,say between 300 and 400 C. The efficiency of the catalyst employed,however, depends to a large extent on whether a carrier or otheradditions are employed. Thus, for example, a catalyst consisting ofnickel and activated with chromium provides a most energetic reductionwhen working in the liquid phase and often leads to the formation ofhydrocarbons whereas nickel deposited on, say, nine times its weight ofkieselguhr furnishes products with a high saponification value.Catalysts prepared from cobalt with additions of a basic nature, such asalumina, magnesia or potassiiun hydroxide are particularly suitable forthe production of alcohols.

The temperatures employed depend, generally speaking, on the nature ofthe material under treatment and' its volatility; temperatures between120" and 400 C. are usually employed. For the reduction of the carboxylgroups into alcoholic groups temperatures between about 150 and 300 C.are advantageously employed. whereas the application of temperaturessubstantially above 250 C. favours the formation of hydrocarbonsespecially when working with active catalysts of nickel as mentionedabove; if catalysts of copper be employed the temperatures may besomewhat higher. The optimum reaction temperature for the production ofa certain reaction product, depends on the nature of the initialmaterial and on the nature of the catalyst employed.

The pressure employed depends on the nature of the initial materials;any pressure of at least 30 atmospheres, preferably from 100 to 300atmospheres, or still higher pressures, such as up to 400 or 500atmospheres, will be applied: straight chain hydroxy-carboxylic.carboxylic acids with branched chains and anhydrides require usuallylower pressures than straight chain saturated acids and their esters.For the reduction of olive oil into the alcohols corresponding to thefatty acids of olive oil for example a pressure above 150 atmospheres isusually necessary whereas hydroxy-octodecanol can be obtained fromcastor oil at lower pressures as for example at 45 atmospheres. Theapplication of higher pressures usually shortens the period of timerequired for the reaction. Thus, for example, stearic methyl ester canbe reduced to octodecanol at a pressure of 300 atmospheres in about halfthe time required when working at a pressure of 200 atmospheres underotherwise equal conditions of working. The period of time required forcarrying out the process also depends on the manner in which thehydrogen is introduced, and on the homogeneous dispersion of thecatalyst within the initial material, intimately stirring and/orspraying the mixture of initial material and catalyst into the reactionvessel providing for example most satisfying results. The process may becarried out continuously or intermittently in any usual and. convcnientmanner.

The quantity of hydrogen employed is advantageously chosenconsiderablyabove that theoretically required for the reduction. In theplace of pure hydrogen gaseous mixtures containing the same may also beemployed, the hydrogen being diluted for example with vapor of water,alcohol, or with nitrogen or carbon dioxide. If desired, diluents inertto the initial materials, such as small quantities of water, orcyclohexane, benzines, phenols, alcohols of high molecular weight may beadded, unsaturated compounds being hydrogenated in many cases during thereaction. By the addition of alcohols the reaction is often facilitatedon working with free acids, esters formed thereby being apparently moreeasily reduced than free acids.

In this manner even carboxylic acids, and their derivatives of theaforesaid nature, having a very high molecular weight, such as oleicmethyl ester, oleic acid or train oil acid, other acids of vegetalorigin, that is of vegetable and animal oils or fats, or oxidationproducts of parafiin wax or glycerides, such as soya bean oil, coconutoil, castor oil, tallow train oils, and the anhydrides, or mixturesthereof with salts of the corresponding acids, and benzoic alkyl estersand esters of homologues of benzoic esters, naphthenic esters and thelike can be converted into alcohols of the aliphatic series, having ahigh molecular weight which hitherto have not been availablecommercially. When employing acids and the like which contain doublelinkages or other readily reducible groups, as for example nitro groups,a hydrogenation of the double linkages, a reduction of the nitro groupsand the like often takes place first during the hydrogenation. Ifhydroxy-carboxylic acids, or their derivatives, such as castor 011, beemployed polyhydric alcohols or primary monohydric alcohols are obtainedin many cases, the original secondary hydroxyl group being apparentlyless resistant to reduction. The alcohols obtained may find usefulapplication in the production, for example, of artificial waxes orcosmetic preparations or of washing, emulsifying or wetting agents bysulphonation, for which purposes they may be employed even in acid bathsor together with hard water. The alcohols may also find usefulapplication for softening natural or synthetic rubber or rubberlikesubstances, such as gutta percha and the alcohols having a long chainmay be esterified with long chain carboxylic acids, such as montanicacid, for the formation of synthetic waxes. The high molecular alcoholsobtained may be esterifled with low molecular carboxylic acids, such asacetic acid, and the esters may find useful application as assistantsolvents in the lacquer or varnish industries or as swelling orgelatinizing agents. Wax-like esters having very valuable properties areoften formed in the reaction according to the present invention, andthese are formed from high molecular alcohols formed and from remaindersof the non-reduced acids, or their derivatives, some portion of theacids, or their derivatives, being reduced to alcohols which latter thenreact with the acid not yet reduced with the formation of esters, thesaponification value being thus reduced by from /8 to A,; on the otherhand the saponification value may be reduced to from to zero if alcoholsin the free andesterified state are mainly desired, a reduction byalmost /2 giving a product consistinl nearly exclusively of ester. Thereduction of glycerides may also be carried out in such a manner thateither these wax-like products solely are obtained or mixtures thereofwith a certain predetermined content of alcohols or of hydrogenatedglycerides. This can be obtained by reducing the pressure and/ortemperature depending on the nature of the initial material and on theactivity of the catalyst employed. These wax-like products may beemployed, as substitutes for bees-wax, spermaceti and the like or may beconverted into alcohols by further treatment according to the presentinvention. The wax-like esters obtained may be employed in the place ofor in conjunction with dressing or impregnating agents in the textileindustries or as assistants in the preparation of polishes.

The following examples will further illustrate how the said inventionmay be carried out in' practice, but the invention is not restricted tothese examples.

Example 1 A mixture of carboxylic acids consisting of lower members ofthe fatty acid series and obtained by the destructive oxidation of a lowmelting point parafiln wax with the aid of nitrogen dioxide isincorporated'with 5 per cent its weight of pyrophorous cobalt powder(obtainable by reducing cobalt carbonate (Merck) in the pulverulentstate at about 350 C. with hydrogen) and then treated at 200 C. withhydrogen at a pressure of 200 atmospheres until the decrease of pressurehas ceased. The catalyst is then filtered off and the filtrate issubjected to distillation at about 12 millimeters (mercury gauge)whereby amixture of alcohols having a hydroxyl value of 290 is obtainedat a temperature between 80 and 200 C. The distillation residue which isobtained in a quantity of about per cent of the whole material subjectedto distillation contains wax-like bodies. The catalysts separated oilcan be employed as such for further operations.

Example 2 A commercial mixture of the anhydrides of palmitic and stearicacids is incorporated with 3 per cent its weight of a catalystconsisting of metallic cobalt and potassium oxide which has beenprepared'by treating a mixture of cobalt carbonate and 1 per cent itsweight of .potassium nitrite at about 350 C. with hydrogen for 36 hours,and the mixture is treated with hydrogen at 230 C. and 300 atmospheresuntil the consumption of hydrogen has ceased. After separating theproduct'from the catalyst by filtration, the former is distilled at 25millimeters (mercury gauge), whereby the alcohols corresponding to theanhydrides employed are obtained at between 180 and 220 C.

Example 3 A catalyst of metallic cobalt which has been treatedwithhydrogen for 36 hours at 360 C. and which has been activated by theaddition of 2 per cent of vanadic acid is added to stearic acid and thelatter is treated with hydrogen at 225 C. under a pressure of 200atmospheres until no more hydrogen is absorbed. The distillation of thereaction product in vacuo after careful removal of the catalyst yieldsmainly octodecyl alcohol having a boiling point of from 203 to 210 C. at11 millimeters mercury gauge about 95 per cent.

and a melting point of 56 C.. the catalyst being removed in order toavoid 'a dehydrogenation. The wax, namely the octodecyl ester of stearicacid, which remains behind after the distillation in some cases may besubjected to reduction again so that the yield of alcohol is practicallycomplete.

A-similar procedure is followed in the reduction of other carboxylicacids, such as butyric acid, succinic acid, colophony, linoleic acid.montanic acid, naphthenic acids, acids from the oxidation of paraiiinand like waxes, or mixtures withsalts of carboxylic acids, as forexample the ammonium salt of stearic acidand the like.

Example 41' A mixture of cobalt and copper carbonates is precipitatedfrom an aqueous solution of 70 parts of cobalt nitrate and 30 parts ofcopper nitrate by adding potassium bicarbonate. After carefully washingthe paste is stirred with 1 part of potassium bichromate, dried,pulverized and treated with hydrogen for 18 hours at 300 C. Stearlcmethyl ester to which about 3 per cent of this catalyst has been addedis treated with hydrogen at 230 C. in a rotary autoclave and thepressure is kept at 200 atmospheres until hydrogen is no longerabsorbed. The contents of the autoclave are subjected to a distillationduring which mainly octodecyl alcohol (melting point 56 C.) passes overbetween 200 and 210 C. at 11 millimeters mercury gauge in a yield of Thewax formed during the reduction and left behind after the distillationmay be subjected to reduction again so that the yield of alcohol isalmost complete. The alcohol may find useful application as a softeningagent in the rubber industry.

Instead of the aforesaid catalyst, a catalyst from commercial cobaltcarbonate may be employed without the addition of bichromate and thereaction may be carried out at 250 C. and at 300 atmospheres. If, inthis case, the reaction be stopped after one hour, the product possessesa saponification. value of 108, is solid, pale yellow and consistsofabout 70 per cent of octodecyl stearate and 15 per cent each ofoetodeeyl alcohol and initial material together with traces ofhydrocarbons. This mixture may find useful application in the productionof sizes for the textile industries.

Example 5 Cobalt carbonate and aluminum oxide are made into a paste withwater ground in a ball mill and kept for 36 hours in a current ofhydrogen at 350 C., the initial compounds being employed in suchquantities that, after the reduction, the mixture contains 17 per centof metallic cobalt. 1 metric ton of commercial soya bean oil to whichabout 7 percent of this catalyst has been added is treated with hydrogenat 230 C. in a stirring autoclave of about 1.5 cubic meters and thepressure is kept at 200 atmospheres until there is no further absorptionof hydrogen, the partial pressure of hydrogen being preferablymaintained -by intermediately blowing off the mixture of hydrogen andhydrocarbons formed from glycerol, such as methane and propane, andreintroducing fresh hydrogen. The contents of the autoclave aresubjected to a distillation during which in addition to a small amountof first runnings mainly octodecyl alcohol having a boiling point offrom 203 to 210 C. at 11 millimeters mercury gauge and a melting pointof about 56 C. passes over.

By working in this manner.v

the glycerine is mainly converted into propyl' carbon atoms. 1

By increasing the temperature to 275 C. the octodecyl alcohol is reducedto octodecane which can thus be obtained in a pure form.

By reducing the pressure to about 150 atmospheres a wax-like substanceis obtained.

Example 6 Finely powdered kieselguhr is incorporated with 10 per cent ofits weight of nickel by treatment with nickel nitrate and reduction andthen the whole is stirred with an aqueous solution of about 3 per centby weight of 'the nickel of potassium bichromate. After drying andgrinding, the mass is treated with hydrogen for 36 hours at 350 C. Soyabean oil is then mixed with 10 per cent of its weight of the catalyticmass and hydrogen is introduced at 200 atmospheres at 200 C. until asample shows a saponification value of from 150 to 170 and an acid valueof from to 20. The product obtained having a melting point of about 60C. is separated from the catalytic mass which latter may be directlyemployed for another operation. The wax-like product shows conchoidalfracture surfaces and possesses a high gloss. The process can also beeasily conducted in such a manner that any desired ratio of ester andhydrogenated soya bean oil or of ester and octodecanol may be obtainedin the products. Generally speaking, products having a highsaponification value possess a high hardness and a high gloss, whereasproducts with lower saponification values, i. e. mixture of the esterand alcohols obtained during the reaction are softer and more mat thanthe aforesaid products and possess a lower melting point. Similarproducts can be obtained from train oil, rape-seed oil and otherglycerides. Products having a saponification value of about that of theinitial material usually possess a crystalline nature like spermaceti.The products obtained may find useful application in the textileindustries for example as dressing or impregnating agents as such or inconjunction with the known agents employed for this purpose.

Example 7 Benzoic ethyl ester is incorporated with 2 per cent of itsweight of a catalyst consisting of cobalt and alumina, prepared from amixture of cobalt and aluminum nitrates by precipitation and subsequenttreatment with hydrogen at from 320 to 350 C., and 2 per cent of thecobalt, whereupon the whole is heated at 210 C. in an autoclave whilestirring and pressing in hydrogen at 200 atmospheres until the pressureremains constant. 80 per cent of the product consists of hexahydrobenzylalcohol which boils at about 180 C. at atmospheric pressure. In the samemanner phthalic esters or esters of other aromatic polycarboxylic acidscan be reduced to the corresponding hydrogenated alcohols.

Example 8 Castor oil is heated at 220 C. in a stirring autoclave with 3per cent of its weight of a catalyst consisting of cobalt activated bypotassium hydroxide and prepared by making cobalt carbonate into anaqueous paste with 1 per cent of its weight of potassium nitrite, dryingand treating the mass with hydrogen at 310 C., while introducinghydrogen until a pressure of atmospheres is attained. After 24 hours thereaction product is drawn off and distilled in vacuo and furnishes at 18millimeters of mercury a distillate passing over between 217 and 240 C.in a quantity of per cent by weight of the castor oil.

By increasing the pressure under otherwise equal conditions of workingthe yield of whole distillate can be increased to more than 95 per centof the theoretical yield; the portion of the V distillate boiling atfrom 230 to 240 C., at 18 millimeters of mercury, is practically purehydroxy-octodecyl alcohol, having a melting point of 65 C. and ahydroxyl value of 382.

Example 9 Adipic di-ethyl ester is incorporated with 3 per cent of itsweight of cobalt which has been prepared by reducing finely powderedcobalt carbonate with hydrogen at 300 C., whereupon the mixture istreated at 190 C. with hydrogen at a pressure of 180 atmospheres untilthe consumption of hydrogen has ceased. After cooling, the oily reactionproduct is filtered off from the cobalt and distilled in vacuo. At from150 to 151 C. and 17 millimeters of mercury 1.6-dihydroxyhexane having amelting point of 42 C. is obtained in a yield of more than 50 per centby weight of the initial material. Hexyl alcohol is obtained in thefractions boiling below 150 C.

Example 10 Montan wax bleached according to the specification of U. S.Patent No. 1,777,766 and having an acid value of about 140 is esterifiedwith methyl alcohol by boiling it under reflux for 4 hours with /5 ofits weight of methyl alcohol and 7 ,3 of its weight of hydrochloricacid, 100 parts of the methyl ester thus prepared having asaponiflcation value of 162 are incorporated with 2 parts of anickel-kieselguhr catalyst consisting of 1 part of nickel deposited on 5parts of kieselguhr and heated with hydrogen at about 180 to 200 C.under a pressure of 100 atmospheres while pressing inhydrogen. As soonas the reaction product has a saponification value of about thehydrogenation is interrupted. After filtering off the catalyst, a palehard wax having a melting point of C. is obtained on cooling.

Example 11 1000 parts of a product, consisting mainly of montanic acidand obtained by bleaching deresinified montan wax with chromic acid andthe reduction of the catalyst.

value of 148, are heated in an autoclave to 220 C. together with acatalyst consisting of 58.8 parts of nickel and 1.2 parts of chromium,while pressing in hydrogen up to a pressure of 200 atmospheres. As soonas the saponification value has been diminished to 88 and the acid valueto 14 the reaction product is drawn oil and saponified with alcoholiccaustic potash. The acids and unsaponiflable matter ar thenprecipitatedwith dilute aqueous sulphuric acid whereby a mixture isobtained which possesses an acid value of 83"- and can be esterified byboiling for 2 hours at about 120 C. with the aid of 0.04 per cent ofconcentrated sulphuric acid. The resulting product possesses an acidvalue of 5.6 and is a hard waxlike mass of white shade.

Example 12 Laurie anhydride is heated in an autoclave to 230 C. togetherwith a catalyst, which has been prepared by reduction of cobaltcarbonate to each 100 molecular proportions of which 2 molecularproportions of potassium hydroxide have been added, while pressing inhydrogen up to a pressure of 200 atmospheres, the quantity of hydrogenconsumed being replenished and the reaction being stopped as soon as theconsump-.

tion of hydrogen has ceased. The reaction product is then freed from thecatalyst by filtration and subjected to distillation in vacuo. 70 percent of th product consists of dodecanol boiling at about 142 C. at 11millimeters of mercury, a small fraction boiling at 220 C. at 2millimeters of mercury.

Example 13 parts of a catalyst prepared by mixing 30 parts of kieselguhrwith a solution of 300 parts of nickel nitrate in 700 parts of water,precipitating with aqueous sodium bicarbonate, filtering, washing,adding a solution of 3 parts of chromic acid, drying, pulverizing andtreating with hydrogen at about 270 C. are introduced into 90 parts offused stearic acid directly after The mixture of stearic acid and thecatalyst is heated in a stirring autoclave at 240 C. while introducinghydrogen until a pressure of 170 atmospheres is attained, heating beingcontinued until a sample shows the saponification value of about 100 ofoctodecyl stearic ester. The product is then separated from the catalystby filtration in a heated filter press. The filtrate solidifies to acolorless waxy mass having a melting point between 50 and 60 C. Tracesof octodecyl alcohol and/or of stearic acid can be easily separated bydistillation. By stopping the reaction before a sample shows theaforesaid saponification value, such as 140, a mixture of the'waxy esterand stearic acid together with a small quantity of alcohol can beotbained; on the other hand, by proceeding until the saponificationvalue is below 100 mixtures of the aforesaid waxy stearic ester andoctodecyl alcohol together with a small quantity of acid can beobtained. In this manner the ratio between the different products can belargely varied. In a similar manner mixtures of waxy esters and/or ofalcohols can be prepared irom mixtures of fatty acids with diiferentnumbers of carbon atoms. In this manner it is possible to prepare waxyproducts having different properties, for example as regards hardness,gloss and possibility of emulsiflcation according to the desired purposeof application of the said products.

Example 14 Olive oil is mixed with 1.5 per cent of a cobalt catalystprepared by making into a paste 100 parts of cobalt carbonate and 0.8part of potassium nitrite, drying, pulverizing and treating withhydrogen at 325 C., and the mixture is heated to 240 C. whileintroducing hydrogen at a pressure of 300 atmospheres until thesaponiflcation value ha decreased to about 60. A product having amelting point of about 55 C. and the shade of a pale bees-wax isobtained; it is softer than a product prepared from the same initialmaterial but in the production of which the reaction is stopped at ahigher saponification value of say 130 and which may be employed forpolishing purposes for example for wood or linoleum. Similar waxyproducts can be obtained from palm oil.

Example 15 Coconut oil having a saponification value of 245 is mixedwith 1.5 per cent its weight of metaliic cobalt prepared by treatingbasic cobalt carbonate containing about 0.5 per cent by weight of sodiumcarbonate with hydrogen at about 350 C. and the mixture is heated to 200C. while forcing in hydrogen at a pressure of 250 atmospheres until thesaponification value has defumes in the soap industries.

creased to about 100. The semi-solid product consists of esters of thealcohols, formed by the reduction of the acids, and the acids of the oiltogether withthe alcohols in the free state, the reduction products ofglycerine and traces of initial oil. If the product be drawn ad from thereaction vessel in the hot state the reduction products of glycerine areevaporated together with water and alcohols of low molecular weightformed from the lower acids of the oil. Products having a saponificationvalue of from 70 to or less possess, when employed in small quantitiesthe agreeable odour of lower alcohols, such as octyl or dodecyl alcoholsand may be usefully employed as perfumes or fixatives for otherperemployed for softening hard fibres.

What I claim is:

l. A process of producing alcohols which comprises treating withhydrogen an anhydride of an aliphatic carboxylic acid, said acidcontainingmore than one carbon atom per carboxyl group, at a temperaturein excess of 200 C., and under a pressure of at least 30 atmospheres inthe presence of a hydrogenating catalyst.

2. A process of producing alcohols which comprises treating withhydrogen an anhydride of an aliphatic carboxylic acid, said acidcontaining more than one carbon atom per carboxyl group, at atemperature in excess of 200 C., and under a pressure of at least 30atmospheres in the presence of a hydrogenating catalyst containingcopper.

3. A process of producing alcohols which comprises treating withhydrogen an anhydride of an aliphatic carboxylic acid, said acidcontaining more than one carbon atom per carboxyl group, at atemperature in excess of 200 C., and under a pressure of at least 30atmospheres in the liquid phase in the presence of a hydrogenatingcatalyst.

4. The process as defined in claim 1 wherein the catalyst is a metalhydrogenating catalyst.

5. The process as defined in claim 1 wherein They may be also saidcarboxylic acid is a high molecular weight fatty acid.

6. The process as defined in claim 1 wherein a mixture of the anhydridesof palmitic and stearic acids are treated with hydrogen.

7. The process as defined in claim 1 wherein the anhydride is laurlcacid anhydride.

8. The process as defined in claim 1 wherein the catalyst is a metalhydrogenating catalyst and the carboxylic acid is a high molecularweight fatty acid.

9. The process as defined in claim 1 wherein a mixture of the anhydridesof paimitic and stearic acids are treated with hydrogen and wherein thecatalyst is cobalt.

10. The process as defined in claim 1 wherein the acid is lauric acidand wherein the catalyst is cobalt.

11. The process as defined in claim 1 wherein the catalyst is a metalhydrogenating catalyst activated by a substance selected from the classconsisting of hydroxides, oxides, carbonates, phosphates, silicates andnitrates of the alkali metals, alkaline earth metals and rare earthmetals.

12. The process as defined in claim 1 wherein a mixture oil theanhydrides of palmitic and stearic acids are treated with hydrogen andwherein the catalyst is cobalt activated with potassium oxide.

OTTO SCHMIDT.

